Draftsman s micrometer-scale



(No Model.) r

E. JONES.

DRAFTSMANS MIGROMETER SCALE. N0. 470,490. Ra tented Mar. 8, 1892.

WITNESSES /N VE N 7'0 wg ATTON Nr'ran .STATES ATENT Orrrcn. I

EDMUND JONES, OF GOLD SPRING HARBOR, NE\V YORK.

D'RAFTSMANS. M lC ROM ETER-SCALE.

SPECIFICATION forming part of Letters Patent No. 470,490, dated March 8,1892.

. Application filed March 2, 1891.

To all whom, it may concern.-

Be it known that I, EDMUND JONES, a citizen of the United States,residing at Gold Spring Harbor, in the county of Suffolk and State ofNew York, have invented a new and 'iseful Improvement inMicrometer-Scales, of which the following is a specification. The objectof this invention is to provide a nicrometer-scale which is simpler andmore ompact in form, more accurate, and more mvenient in use than thoseheretofore genally employed.

To the end that my invention may be clearly lerstood, I shall omit allpreliminary deription and proceed to a detail description rereof, afterwhich I shall distinctly point .ut and claim the invention. Reference isto be had to the accompanying .lrawing, forming a part of thisspecification, in which the figure is a face view of a micrometer-scaleembodying my invention.

The scale thus illustrated as an example is designed to give thethousandths of an inch, and to this end the straight transversezero-line A is drawn in this instance exactly ten inches in lengtlranddivided into one hundred parts, Which are marked by parallel lines B,crossing the zero-line A at right angles thereto. The lines B extendfrom the zero-line A in one direction, which We will term downward, to aunit-line 0, parallel to, exactly one inch below, and of the same lengthas the zero-line A, and upward and beyond the zero-line A to any desireduniform length, preferably about that of the longest lines it isexpected to measure with the scale.

Above the zero-line are transverse lines D E F, &c., parallel to and atdistances from the zero-line A of, respectively, one, two, three inches,850., and numbered 1 2 3, 8m, accordingly. The inch-long extensions B Bof the two outside sidelinesB below the zeroline A are each divided intoten equal parts, each thus one-tenth of an inch long, marked by points ab c, 850,, and a b c, &c.,respectively. The pairs of points at, b c, cd, d e, ef,f' g, g h, h i, U, andj'lo are consecutively connected bystraight lines, which thus intersect the longitudinal lines B obliquelyat points whose distance from the zero-line unit extensions 13' 13*.

Serial No. 383,481. (No model) such intersecting lines B are in numberdistant from said initial points a b c, &c., of the oblique lines. Theinitial points a b c, &c., are therefore marked O, (1/10,) &c., and theoblique lines a b, b c, &c., at their intersections with the lines B areeach marked from 1 to 100, commencing with their initial points a b c,850., Thus to measure two and six hundred and sixty-six thousandthsinches by this scale take off the distance from the intersection of theoblique line marked with the line B, marked 66, on said line B to thetransverse line E, marked 2. In asimilar manner a scale may beconstructed to measure to any fraction of any unit of length, thedistance between the zero-line A and line C being made equal to saidunit, the parts B 13 subdivided to give fractions of said unit, and

the transverse space between said extensions tudinal lines B to thedesired fraction of the aforesaid fraction, which lines B are inter-'sected by oblique lines connecting consecu tively alternate subdivisionsof the extreme The distance between the extreme unit-extensions B B isof course immaterial, save for convenience.

This scale may be etched on glass or metal for a standard by any of theaccurate processes in vogue and other scales adjusted therefrom,measurements being taken off the same by dividers or calipers orotherwise.

The dotted lines shown in the drawing illustrate the plan of a scale tomeasure to tWo-hundredths of an inch, according to my invention.

I claim as my invention Theimproved micrometer-scale herein shown anddescribed for measuring divisions of a unit smaller than aone-hundredth, the same consisting of a plane surface havingthereonparallel straight lines A O, &c., said units distance apart, butof equal and as many as ten times said units length, equidistantstraight lines B, in number a multiple of ten,

intersecting the lines A O at a right angle the line B and intersectingthe lines B 0band subdividing the lines AG into a multiple 1ique1y,asset forth. of ten equal parts, the parts B B of the outside lines B,connecting the ends of the lines 1 EDMUND JONES A 0, being subdividedinto ten equal parts, Witnesses:

and straight lines connecting the divisions of CLARENCE L. BURGER,

the line B with the succeeding divisions of ROSOOE G. TOOMBs.

It is hereby certified that in Letters Patent No. 470,490, granted March8,1892 upon the application of Edmund Jones, of Oold Spring Harbor, NewYork, foran improvement in Drattsmens Mierometer-Soales, an-errorappearsin the printed specification requiring the following correction,viz.: In lines 98 and 99, page 1, the clause and. as many as ten times,should read and many, as ten, times and that the said Letters Patentshould be read with this correction therein that same may conform to therecorri of the case in the Patent Office.

Signed, eountersigned, and sealedj this 15th day of March, A. D. 1892.

[ -1 CYRUS BUSSEY,

Assistant Secretary of the Interior.

Letters Patent No.

Oountersigned W. E. SIMONDS,

Commissioner of Patents.

Correction m

